Harvey S C, Masabanda J, Carrasco L A P, Bromage N R, Penman D J, Griffin D K
Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK.
Cytogenet Genome Res. 2002;97(1-2):76-80. doi: 10.1159/000064036.
Sex determination in the Nile tilapia, Oreochromis niloticus, is primarily genetic, with XX females and XY males. A candidate sex-determining region in the terminal region of the largest chromosome pair has been identified by analysis of meiotic chromosomes. This region shows an inhibition of pairing and synapsis in the XY genotype, but not in XX or YY genotypes, suggesting that recombination is inhibited. Here we show that chromosome microdissection and subsequent amplification by degenerate oligonucleotide-primed PCR (DOP-PCR) can be used to produce in situ hybridization probes to this largest pair of O. niloticus chromosomes. Furthermore, analysis of the comparative hybridization of X and Y chromosome-derived probes to different genotypes provides the first demonstration that sequence differences exist between the sex chromosomes of O. niloticus. This provides further support for the theory that this chromosome pair is related to sex determination and further suggests that the sex chromosomes are at a very early stage of divergence.
尼罗罗非鱼（Oreochromis niloticus）的性别决定主要由基因决定，存在XX雌性和XY雄性。通过对减数分裂染色体的分析，已在最大染色体对的末端区域鉴定出一个候选性别决定区域。该区域在XY基因型中表现出配对和联会抑制，但在XX或YY基因型中没有，这表明重组受到抑制。在这里，我们表明染色体显微切割以及随后通过简并寡核苷酸引物PCR（DOP-PCR）进行的扩增可用于制备针对尼罗罗非鱼这对最大染色体的原位杂交探针。此外，对X和Y染色体衍生探针与不同基因型的比较杂交分析首次证明尼罗罗非鱼的性染色体之间存在序列差异。这为该染色体对与性别决定相关的理论提供了进一步支持，并进一步表明性染色体正处于分化的非常早期阶段。
